Storage tank for volatile liquids



Aug. 2, 1938. v. A. DE CASTRO 2,125,771

STORAGE TANK FOR VOLATILE LIQUIDS Filed March 7, 1936 3 Sheets-She Hll Aug. 2, 1938. v. A. DECASTRO 2,125,771

STORAGE TANK FOR VOLATILE LIQUIDS Filed March 7; 1956 3 sheets-Sheet 2 1938. v A. DE CASTRO 2,125,771

STORAGE TANK FOR VOLA'IILE LIQUID S Filed March 7, 1936 3 Sheets-Sheet 3 Patented Aug. 2, 1938 STORAGE TANK PATENT OFFICE j I Vincent A. de Castro, Habana, Cuba f j Application March I, 1936, Serial No. 67,694

15Claims.

expensive and readily impaired flexible materials, or on a more or less imperfect closure due to the fact that certain sealing members rising and failing with the floating cover would press against the interior of the shell. These means could not possibly attain a vapor-tight condition due to irregularities in the surface of the sides of the tank, and because insumcient pressures were employed as, otherwise, the cover could not descend. The primary object of my invention-is to provide means to prevent or diminish the loss by evaporation of the storedliquid while the latter is 'being iilled into the tank and while such liquid is held in storage, said means consisting primarily of successively formed liquid seals between the floating cover and the sides or shell of the tank; and hence neither a flexible material is required nor a closure by means of a mechanical pressure.

Another object of my invention is to provide v means to replenish and to drain the liquid constituting the liquid seal upon the use of which depend the other objects sought.

A still further object of my invention is to.

' pro've means whereby the floatingcover and sealing media hereinafter described shall be con-; strained to maintain certain convenient relative provide, while avoiding the use of flexible material or need for mechanical pressure, a new, improved simple economically-manufactured and I economically-operated wholly hermetic tank,

with a limiting cover, in which tank the evaporation losses and flre hazards are reduced to;

minimum. I achieve these objects and such other objects as may hereinafter appear or be pointed out, in the manner illustratively exemplifled in the three embodiments shown in the accompanying drawings. wherein:

: Figure 1 a a vertical sectional view on line l--l of Figure 2, drawn to a relatively small 55 scale, oi one embodiment of my improved tank,

showing the floating cover at" the lowest position in its travel.

Figure 2 is a top plan view of the embodiment depicted in Figure 1. g

Figure 3 is a fragmentary vertical section of the embodiment shown in Figure 1, but drawn to. a larger scale, and showing the floating cover at the highest position in its travel.

Figures 4, 5 and 6 are fragmentary..,vrtic sections of a .second embodiment of my improved tank, all three views showing the covenat its lowest position. i

Figure '7 is a' fragmentary vertical section of, a third embodiment of the tank of my invention.

' Figure 8 is a detailed view of one embodiment 15 of a column-guide for the cover.

Figure 9 is a similar view of a second embodi ment of a column-guide. v

Referring to Figures 1, 2 and ,3, I have illustratively shown one embodime t of .my tank" with a shell of same of sub tantially cylin-- drical construction, and provided with a roof or cover III, which also is substantially rigid and cylindrical andadapted for 'freelyrising and descending as it floats on the stored liquid mm 25 accordance with principles well-known in the art.

I provide means whereby the ascending and descending movement of cover ill can take place without in the least impairing the'hermeticallysealed relationship of the cover witl; reference to the portion of the tank containing the stored liquid, as follows. Y

As will be noted from the drawings, at the periphery of the floating cover Ill, I have provided an upwardly opening annular trough l2, adapted to'receive water or other sealing fluid It, and I have also provided, at suitable'varying heights along the shell 50, and forming part thereof, similar upwardly opening annular troughs ll, I5 and I6, having sealing fluid ii and adapted to receivesealing members it, Is and 20, consisting of very thin metal sheets duly reinforced with angles or other means.

.Esch of these members is provided with two vertical depending flanges 2i and 22 respectively, one of these depending flanges being adapted to extend downwardly into the sealing liquid i3 and the other into the sealing liquid ll, thereby constituting a liquid seal between the cylindrical shell it and the floating cover l0.

' Columns ll, aflixed to the bottom of the tank,

provide a support for the cover when in its lowest position.-

fact um a liquid seal is maintained at all is the keystone of my invention. The condition of continuous hermeticity is attained as follows.

Regardless of whether or not, with variations in the level of the stored liquid. the floating cover rises or descends, there will always be one of the sealing members II, I! or 20, with one depending flange 2i immersed in the liquid i3,

' of the trough i2 and with the other depending 1o flange 22 immersed in the liquid ll, of one of the troughs I, II or I of the shell of the tank, thus maintaining a liquid seal and the condition of hermeticity. This occurs since, as the floating cover it rises, it picks up each sealing memher in. turn, and these sealing members will ride up with the cover ll while the depending flange II of one of the sealing members i8, i! or 2. projects downwardly into the liquid it within the trough, and the other depending flange 21 projects downwardly into the liquid ll of the troughs i4, i5 and ii. on the other hand, as the floating-deck descends it leaves behind one after another of the sealing'members, suspended from the vertical wall of its corresponding trough M, II or it on the shell of the tank, so

that the condition of hermeticity is maintained in a similar manner as described for the upward movement of the cover.

In the tank of my present invention, assuming that the sealing member which is acting to maintain a condition of hermeticit'y, be seated with its horizontal annular flange resting on the top edge of the vertical wall of a trough on the side of the tank, then a rise in temperature will increase 5 the pressure of the air-vapor mixturecontained between the tank wall, the sealing member and the floating cover but only until this pressure reached the amount which Just sustains the weight of. the said sealing member, at which time 40 the pressure ceases to increase and the volume of the air-vapor mixture increases, gradually lifting the sealing medium as the temperature continues to rise. In the same manner, a drop in temperature will cause a decrease in the volume of the 45 air-vapor mixture and the sealing member, acting 50 lar trough.

The riseor fall of a sealing member automatically compensates for variations in pressure or vacuum but, it being advisable to limit the values of pressure and vacuum to certain predetermined 55 maxima, there are provided pressure-relief safety valve 5i and vacuum-relief safety valve 44, which are accessories well-known in the art. Whenever the pressure within the air-vapor space 3|, reaches a predetermined value, valve 5| auto- 50 matically opens and suflicient volume of the airvapor mixture escapes into the air to reduce the pressure to less. than a predetermined maximum. Similarly, whenever the partial vacuum in the air-vapor space 34 reaches a predetermined 5 value, valve It automatically opens and sumcient volume of the outside air flows into the air-vapor space ll to reduce the value of the vacuum to less than a I predetermined maximum. Although shown only in Figure 6, valves II and. N are 70 equally applicable to the three embodiments of the present invention, and all these valves are connected to the end of the U-tube 43 which lies outside of the tank. U-tube It passes through the floating cover in an hermetic Joint and the 75, free end, li, lies within the air-vapor space 34,-

such end Ii serving as an outlet for the excess air-vapor mixture, and as an inlet for the admittance of outside air, depending on whether valve" II or valve 44 shall at the time be functioning.

The foregoing and the following description applies equally as well to the second embodiment shown in Figs. 4, 5 and 6, and to third embodiment shown in Figure '7, in all of which figures the same numerals describe the like parts as Figures 1, 2 and 3. ,The main difier'ences among the three embodiments are that whereas in the first embodiment the top trough iii and top sealing member 20 serve to maintain a vaportight relationship when the cover is at the top of its travel, in the second embodiment this function is assumed by an annular flange Ii, aflixed to the shell and a cylindrical skirt 42 depending from the flange 4|; while in the third embodiment, (Fig. 7) the vapor-tight relationship is maintained within the limits of the available travel of the cover by only one deep trough i4 and one sealing member II.

In Figure 5 there is shown a means for constraining the seallng member or members to travel along definite paths which means, although applied to the ,tank of the second embodiment, are equally applicable to that of the first and the third embodiments. I have provided roller guides 21 and 28 on the outer depending flanges of the sealing media, which roller guides 21 and 28 are constrained to follow rail 1 in the drawings) to allow for variations from the I vertical of the guides 2i and 30. 1

Female stops, 3!; are placed at intervals along the sealing members like", while directly below on the corresponding sealing member like i8 are provided male stops 33. When a sealing member carries along the next sealing member above it, the relative position is maintained by the male stops 33 engaging the female stops 32.

In Figure 6 only, I have shown the means proposed for replenishing the sealing liquid and for draining the gasoline or other liquid left in the troughs upon the descent of the level.of the stored liquid II. For clearness, the a means for one trough only have been depicted. It will be understood that the other troughs onthe shell are similarly provided as by branches of pipe 35 which hermetically passes through theannular flange ll of the skirt, and through theannular trough l5 and serves to feed sealing liquid to the trough H by opening of a valve 36.

An overflow pipe 31, is provided for each trough i4, i5, etc. and has branches ll and 39 provided to keep the liquid in the trough at a certain level. Inasmuch as the liquids stored, probably gasoline, will be lighter than the sealing liquid, probably water, and not miscible therewith, it will be evident that this gasoline will float on the water, and the opening of valve 30 will serve to add water to the troughs so that any gasoline left in Referring specially to Fig.8, in order to co n-- strain the floating deck to follow definite paths the troughs will overflow through the branch In Ward and downward movements, I have pose oi retaining any vapors which may be found between the cover it andthe liquid Ii. 'Bracing 24 at top of these colunms 23 maintain these more rigid, while 26 is a stop to support rooi' l0 when at its lowest position.

if desired, these column guides 23 can be wholly dispensed with, the cover being guided in its rise and fall, by the sealing members l8. l9, etc. In Figure 9 a second embodiment is shown of a column guide M to constrain the floating deck to follow definite paths in its upward and downward movements. This embodiment differs from that depicted in Figure 8, in that, at all times, throughout the available height of the tank, and regardless of the relative position between the floating deck Ill and the column guide II, a liquid seal is maintained between such deck and said column.

' This continuous liquid seal being maintained as follows. The floating deck I0 is provided with an upwardly open annular trough afllxed to liquid Qt and with the other adapted to immerse in'the sealing liquid it. It will be evident that no matter whether the cover rises or descends, within the available height of the container a continuous seal will be maintained between the depending skirts Just mentioned of the sealing medium and the corresponding sealing liquids it and lt; ion-upon the rise of the cover to suchan extent that the depending smrt of the sealing member 49 touches the bottom of the trough iii,

the sealing member to will .be carried upwards 1 hatches and other accessories well-known to those skilled in the art.

I do not limit myself to the embodiments herein described, as it will be understood that various modifications may he made without departing l from the general features of the invention.

What I claim and desire to secure by letters shell adapted to contain fluid, a roof adapted to overlie and float upon the fluid so contained, sealing means between the roof and the shell, comprising, an upwardly facing annular trough on the roof, a plurality of upwardly facing troughs spaced vertically and fixed to the inner face of the shell and decreasing in. width, from lower to upper, and a sealing means for each shell trough including spaced depending flanges each being telescopically receivable in'the one above.

2. A tank and roof construction comprising a shell adapted to contain fluid, a roof'adapted to overlie and float upon the fluid so contained, sealing means between the roof and the shell, comprising, an upwardly facing annular trough on the roof, a plurality of upwardly facing troughs spaced vertically and flxed to the innerface of r the shell, and a sealing means for each shell the sealing means being wholly receivable each in the one above it, as the roof ascends.

3. A tank and roof construction comprising a, shell adapted to contain fluid, a root adapted to overlie and float upon the fluid so contained, sealing means between the roof and the shell, comprising, an upwardly facing annular trough onlthe roof, a plurality of upwardly facing troughs spaced vertically and fixed to the inner face of the shell, and a sealing means for each shell trough including spaced depending flanges, one flange of each sealing means overlying the rooi trough, and the other overlying its shell trough, each shell trough being wider than the one immediately above it. v

4. A tank and roof construction comprising a shell adapted to contain fluid, a roof adapted to overlie and float upon the fluid so contained, sealing means between the roof and the shell, comprising, an upwardly'facingannular troughon the roof, a plurality of'upwardly facing troughs spaced vertically and flxed to the inner face of the shell, and a sealing means for each shell trough including spaced depending flanges; the shell troughs increasing in width, and the spacing of the. flanges onthe sealing means decrwsihg in width, from the top to the bottom of the shell.

'5. A tank and roof construction comprising a shell adapted to contain fluid, a roof adapted to overlie and float upon the fluid so contained, sealing means between the roof and the shelhcomprising, an upwardly facing annular trough on the roof, a plurality of upwardly-facing troughs spaced vertically and flxed'to the inner face of the shell, and a sealing means for each shell trough including spaced depending flanges, one

flange ofeach sealing means overlying the roof trough, and the other overlying its shell'trough, the shell troughs increasing in width, and the spacing of the flanges on the sealing means decreasing in width, from the top to the bottom of the shell.

6. A tank and roof construction comprisingu shell adapted tocontain fluid, a roof adapted to overlie and float upon the fluid so contained, seal-- ing means between the roof and the shell, comprising, an upwardly facing annular trough on the roof, a plurality of upwardly facing troughs spaced vertically and flx'ed to the inner idea of the shell, and a sealing means for each shell trough including spaced depending flange -one flange of each sealing means overlying the roof trough, andthe-other overlying its shell trough,

fixed guide means for the roof, and liquid seal n'ieans between the guide means and the roof.

. 7. In a; tank for volatile Munich, in comhinato float upon liquid in the tank, an annular trough at the edge of the cover adapted to receive a sealing liquid; one depending iiange of the narrowest of the freely movable sealing members ento a level higher than that. of the trough on the 'shell gaging freely with the widest trough on the wall, and one depending flange of the widest sealing member engaging freely with the narrowest of such troughs,the depending flanges of other sealing members and troughs oo-acting similarly.

8. In a tank for volatile liquids, in combination, a wall, a plurality of annular troughs secured to the wall, interiorly', at different levels and adapted to receive sealing liquid, each of such troughs being wider than those above it; a like plurality of annular sealing members with inverted U cross-section positioned at different levels, each sealing member being wider'than those located beneath it, and independent therefrom and from the wall, all sealing members being freely vertically movable; a freely vertically movable, independent, cover having a trough adapted to receive sealing liquid; one depending flange of each sealing member being adapted to engage freely with one of the said troughs on the wall, the narrowest sealing member co-acting with the widest trough on the wall, and the widest sealing member co-acting with the narrowest of such troughs, other sealing members co-acting in a similar proportionate arrangement, the other flange of each sealing member being adapted to freely engage -with the roof trough whereby when the cover sealing member being wider than thoselocated beneath it, the highest of such sealing members being attached to the wall while the others are independently and freely vertically movable; a freely vertically movable, independent, cover adapted to float upon liquid in the tank, an annular trough at the edge of the cover adapted to receive a sealing liquid; the flxed sealing member acting. when the cover is nearing its highest position, and the other sealing members acting below the highest position, one depending flange of the narrowest of thefreely movable sealing members engaging freely with the widest trough on the wall, and one depending flange of the widest sealing member engaging freely with 'the narrowest of such troughs, the depending flanges of other sealing members and troughs co-acting similarly.

10. A tank and roof construction comprising a shell adapted to contain fluid,,a roof loosely receivable in said shell and adapted to overlie and float upon fluid contained in said shell; sealing means between the roof and the shell, comprising, an up-turned annular trough on the roof, an annular membenof general L-shape in crosssection, flxed to one side of the shell with its stem spaced from the shell so as to form with such shell an upwardly facing annular trough,

and a loosely-mounted annular sealing member having two spaced depending flanges one overlying the trough onthe roof and the other overlying the trough on the shell, the roof being of such dimensions as to allow it to freely ascend 11; A tank andlroof construction comprising,

' aibell adapted to contain fluid, a roof freely re- 'oeivable insaid shell and adapted to overlie, and

float upon, fluid contained in said shell, and sealgeneral L-shape in cross-section, flxed to the shell, and forming with said face, an annular trough adapted to receive a sealing liquid; a separate, freely vertically movable circular cover adapted to float upon liquid contained in the tank and of lesser diameter than that of said annular trough, an annular trough on the cover adapted to receive a sealing liquid; and means for establishing a liquid seal between the trough of the wall and the trough of the cover, which comprises an annular, freely vertically movable, inverted sealing member, U-shaped in cross-section, one leg of which overlies the trough of the wall and the other leg of which overlies the trough on the cover; flxed guide means for the cover, and liquid seal means between the flxed guide means and the cover. A

13. A tank and roof construction comprising a shell adapted to contain fluid, a roof adapted to overlie and float upon fluid contained in the shell,

sealing means between the roof and the shell, comprising, an-upwardly facing annular trough on the roof, a plurality of upwardly facing annular troughs spaced vertically and fixed to the inner face of the shell and decreasing in width progressively upward, and a ,sealing member foreach shell trough each including spaced depending flanges, the spacing of which flanges decreases in width progressively downwardly, each sealing member being telescopically receivable in the one above it.

14. A tank and roof construction comprising,

cular roof adapted to overlie and float upon fluid contained in said shell, sealing means between the roof and the shell, comprising, an upwardly facing annular trough on the roof, a plurality of annular pieces of L-shape in cross-section and flxed to the shell so as to form, with the shell, a plurality of upwardly facing annular troughs, spaced vertically, and decreasing in width progressively E upwardly, and an annular sealing piece for each shell trough, including spaced depending flanges, one flange of each sealing piece overlying theroof trough, and the other overlying its shell trough, the roof being of lesser diameter than the inner diameter of any shell trough.

piece for each shell trough including spaced depending flanges, the spacing of which decreases in width progressively downward.

, vmcmrr A. casino; 

